Chronic hepatitis B virus (HBV) infection, for which there is currently limited treatment, constitutes a global public health problem of enormous dimensions. Chronic carriers of HBV, estimated to number more than 300 million world-wide, are at risk for development of chronic active hepatitis, cirrhosis and primary hepatocellular carcinoma.
Many vaccines which are currently available require a preservative to prevent deterioration. A frequently used preservative is thiomersal which is a mercury-containing compound. Some concerns have been raised about the use of mercury in vaccines, although commentators have stressed that the potential hazards of thiomersal-containing vaccines should not be overstated (Offit; P. A. JAMA Vol. 283; No:16). Nevertheless it would be advantageous to find new and potentially safer methods of preparation of vaccines to replace the use of thiomersal in the manufacturing process. There is thus a need to develop vaccines which are thiomersal-free, in particular hepatitis B vaccines.